Forcasts

The next few days will bring snow, rain, tornadoes, and blizzards to areas of plains and Midwest.

Severe Weather Outlook

12z SPC outlook for 12/19/2011

This outlook provides a look at the main area of concern for a tornado setup in the state of Texas.

From outlook

”

...CNTRL AND E TX TODAY/TNGT...
50+ KT SLY LLJ WILL PERSIST AHEAD OF W TX UPR SYSTEM TODAY AND
TNGT...MAINTAINING NWD TRANSPORT OF MOISTURE ACROSS THE SRN PLNS AND
WRN PARTS OF THE LWR MS VLY. NEITHER SATELLITE NOR SFC DATA SHOW
PRESENCE OF ESPECIALLY MOISTURE-RICH AIR OVER THE NWRN GULF FOR THE
LLJ TO TAP. NEVERTHELESS...THE DATA DO SUGGEST THAT AHEAD OF
PACIFIC COLD FRONT...SFC DEWPOINTS WILL RISE INTO THE UPR 50S F AS
FAR N AS THE RED RIVER LATER TODAY. VALUES IN THE MID TO UPR 60S
APPEAR LIKELY OVER THE MIDDLE TX GULF CSTL PLN...WITH PW AOA 1.25
INCHES.
HEIGHT FALLS/FORCING FOR ASCENT ON LEADING EDGE OF W TX UPR
VORT...LOW-LVL UPLIFT ALONG ASSOCIATED PACIFIC FRONT...AND WEAK SFC
HEATING SHOULD FOSTER DEVELOPMENT OF AN ARC OF SFC TO NEAR SFC-BASED
TSTMS ALONG THE FRONT FROM ERN PARTS OF THE HILL COUNTRY NWD TO N
CNTRL TX BY MID TO LATE AFTN. THIS ACTIVITY SHOULD FAIRLY QUICKLY
EVOLVE INTO A BROKEN LINE AND CONTINUE E ACROSS THE I-35 CORRIDOR BY
EARLY EVE. OTHER...PERHAPS MORE DISCRETE STORMS MAY FORM A BIT
LATER IN THE DAY OR THIS EVE ALONG PRE-FRONTAL CONFLUENCE AXIS OVER
THE MIDDLE TX GULF CSTL PLN E/NE TO NEAR THE CLL AREA.
AS THE UPR LOW CROSSES THE SRN PLAINS...A BAND OF 60 TO 80 KT SSW TO
SWLY 500 MB FLOW WILL OVERSPREAD WARM SECTOR...YIELDING SHEAR/WIND
PROFILES FAVORABLE FOR SUSTAINED STORMS/SUPERCELLS. ALTHOUGH THE
STRONGEST FORCING FOR ASCENT AND SHEAR WILL RESIDE OVER N
TX...TEMPORAL BACKING OF MID LVL WINDS AND COMPARATIVELY WEAK LOW
LVL BUOYANCY /SBCAPE AOB 250 J PER KG/ SHOULD LIMIT THE SVR THREATS
TO LOCALLY DMGG WIND AND PERHAPS AN ISOLD TORNADO FROM LINE SEGMENTS
CONTAINING EMBEDDED LEWPS/SMALL BOWS. MORE SUBSTANTIAL SBCAPE /WITH
VALUES AOA 1000 J PER KG/ IS EXPECTED FARTHER S FROM CNTRL TX ESE TO
THE MIDDLE TX GULF CST. WHILE WIND PROFILES IN THIS REGION WILL BE
WEAKER RELATIVE TO POINTS N...ABSENCE OF TEMPORAL BACKING OF FLOW
AND PRESENCE OF GREATER INSTABILITY/WEAKER LINEAR FORCING FOR ASCENT
MAY SUPPORT A COUPLE SUPERCELLS CAPABLE OF TORNADOES...IN ADDITION
TO DMGG WIND. SOME OF THIS ACTIVITY MAY REACH THE CST
TNGT...AFFECTING AREA FROM PSX TO HOU/GLS.
THE SVR THREAT SHOULD DIMINISH LATER TNGT/EARLY TUE AS UPR LOW
CONTINUES NE INTO KS AND FORCING/SHEAR WEAKEN OVER SE TX."

Snow Outlook

With the potential for major amounts of moisture to intrude the Central United States, temperatures below freezing and winds in excess of 35mph Blizzard warnings have been posted.

A BLIZZARD WARNING MEANS SEVERE WINTER WEATHER CONDITIONS ARE
EXPECTED OR OCCURRING. FALLING AND BLOWING SNOW WITH STRONG WINDS
AND POOR VISIBILITIES ARE LIKELY. THIS WILL LEAD TO WHITEOUT
CONDITIONS...MAKING TRAVEL EXTREMELY DANGEROUS. DO NOT TRAVEL. IF
YOU MUST...HAVE A WINTER SURVIVAL KIT WITH YOU. IF YOU GET
STRANDED...STAY WITH YOUR VEHICLE.

The Storm Prediction Center has highlighted a area of concern for Tuesday 3/22/11 for the possibility of severe weather (see below).

Day 2 Outlook

Day 2 Probabilities

SPC Text

..SYNOPSIS
MODELS REMAIN CONSISTENT CONCERNING THE LARGE-SCALE PATTERN
EVOLUTION THROUGH THIS FORECAST PERIOD. A BLOCKING UPPER RIDGE IS
PROGGED TO EVOLVE TO THE EAST OF THE CANADIAN ROCKIES...WITH A LARGE
HIGH CENTER STRENGTHENING OVER THE CENTRAL CANADIAN PROVINCES DURING
THE DAY TUESDAY. AS THIS PROCEEDS...A LARGE UPPER TROUGH...LIFTING
THROUGH THE INTERMOUNTAIN WEST AND ROCKIES BY 12Z TUESDAY...SHOULD
GRADUALLY BE FORCED EASTWARD INTO AN INCREASINGLY CONFLUENT REGIME
ACROSS THE UPPER MIDWEST...WHILE ANOTHER AMPLIFYING SHORT WAVE
TROUGH DIGS TOWARD THE CALIFORNIA COAST.
WITHIN THE LEAD WAVE...A SIGNIFICANT EMBEDDED IMPULSE EMERGING FROM
THE SOUTHERN ROCKIES IS STILL FORECAST TO PIVOT INTO AND NORTHEAST
OF THE MID/LOWER MISSOURI VALLEY IN INCREASINGLY NEGATIVELY TILTED
FASHION BY TUESDAY EVENING. THIS SHOULD RESULT IN STRONG MID-LEVEL
HEIGHT FALLS OVERSPREADING THE WARM SECTOR OF A SUB 1000 MB SURFACE
LOW MIGRATING ACROSS THE MID MISSOURI VALLEY AND UPPER PORTIONS OF
THE MIDDLE MISSISSIPPI VALLEY. FORCING WILL BE FOCUSED ALONG AND
NORTH OF A STRONG MID/UPPER JET STREAK...AROUND 90 KT AT 500
MB...WHICH WILL GRADUALLY VEER FROM A SOUTHWESTERLY TO WESTERLY
COMPONENT AS IT PROPAGATES ACROSS THE SOUTH CENTRAL PLAINS/OZARK
PLATEAU AND MIDDLE MISSISSIPPI VALLEY.
GIVEN THE STRENGTH OF THE LARGE-SCALE FORCING FOR UPWARD VERTICAL
MOTION...AND THE SIZE OF THE AREA THAT IT COULD IMPACT...A
CONSIDERABLE INCREASE IN CONVECTIVE POTENTIAL IS ANTICIPATED ACROSS
MUCH OF THE PLAINS...THE MID/UPPER MISSISSIPPI AND OHIO VALLEYS AND
UPPER GREAT LAKES REGION. COUPLED WITH THE LIKELIHOOD THAT THIS
WILL BE PRECEDED BY THE EASTWARD ADVECTION OF WARM ELEVATED MIXED
LAYER AIR THROUGH MUCH OF CENTRAL U.S...THE RISK FOR SEVERE
THUNDERSTORMS COULD BE SUBSTANTIAL...AS VERTICAL SHEAR BECOMES
STRONG. HOWEVER...IT STILL APPEARS THAT THIS POTENTIAL MAY NOT BE
FULLY REALIZED. OBSERVATIONAL AND MODEL DATA CONTINUE TO INDICATE
THAT A SUBSTANTIVE INLAND INCREASE IN BOUNDARY LAYER MOISTURE OFF
THE GULF OF MEXICO TO THE WARM SECTOR OF THE LOW IS
UNLIKELY...THROUGH AT LEAST THIS PERIOD...AS LOW-LEVEL RIDGING IS
SLOW TO LOSE INFLUENCE OVER THE CENTRAL AND EASTERN GULF.
STILL...LOW-LEVEL MOISTURE CHARACTERIZED BY MID 50S TO LOWER 60S
SURFACE DEW POINTS SHOULD BE SUFFICIENT TO SUPPORT SEVERE
THUNDERSTORMS...WHICH COULD BECOME FAIRLY NUMEROUS OR WIDESPREAD
ACROSS UPPER PORTIONS OF THE MIDDLE MISSISSIPPI VALLEY LATE TUESDAY
AFTERNOON AND EVENING.
..PLAINS/MISSISSIPPI VALLEY
CONFIDENCE IS GREATER THAT SURFACE DEW POINTS NEAR OR JUST ABOVE 60F
MAY BECOME COMMON IN A CORRIDOR FROM NEAR THE SURFACE CYCLONE EAST
SOUTHEASTWARD ALONG A STALLED FRONTAL ZONE EXTENDING INTO THE OHIO
VALLEY. BENEATH THE NOSE OF A PLUME OF ELEVATED MIXED LAYER
AIR...THIS IS EXPECTED TO BE SUFFICIENT TO CONTRIBUTE TO MIXED LAYER
CAPE IN EXCESS OF 1000 J/KG...NEAR THE MISSOURI RIVER EASTWARD
ACROSS PARTS OF SOUTHERN IOWA AND NORTHERN MISSOURI BY PEAK HEATING.
STORMS ARE EXPECTED TO DEVELOP AS STRONGER FORCING FOR ASCENT
OVERSPREADS THE REGION DURING THE LATE AFTERNOON. THIS SHOULD
INCLUDE A FEW SUPERCELLS BEFORE GROWING UPSCALE INTO A MESOSCALE
CONVECTIVE SYSTEM...WHICH SHOULD TRACK EAST SOUTHEASTWARD ALONG AND
JUST SOUTH OF THE FRONT. WITH THE BOUNDARY LAYER JUST TO THE NORTH
OF THE FRONT EXPECTED TO BE RATHER COOL AND STABLE...TORNADIC
POTENTIAL WITH STORMS CROSSING THE BOUNDARY MAY BE LIMITED.
DAMAGING WINDS AND LARGE HAIL STILL APPEAR TO BE THE PRIMARY
CONCERNS WITH THE CONVECTION...WHICH COULD CONTINUE AND SPREAD INTO
PARTS OF THE LOWER OHIO VALLEY TUESDAY NIGHT.
ADDITIONAL...MORE WIDELY SCATTERED...STORM DEVELOPMENT IS EXPECTED
ALONG THE DRY LINE TO THE SOUTH OF THE LOW...ACROSS EASTERN PORTIONS
OF THE CENTRAL AND SOUTHERN PLAINS DURING THE LATE AFTERNOON AND
EVENING. SUPERCELLS ARE POSSIBLE...PRIMARILY WITH THE RISK FOR
LARGE HAIL AND LOCALLY DAMAGING WIND GUSTS.
..KERR.. 03/21/2011

Pros:

Terrain

Some Cape

Good Temps

Strong Shear

Cons:

Poor Hodographs

As with most Iowa Setups there are capping issues.

Poor Crossovers.

For those chasers who live in Iowa or can’t wait for a Nice setup I say go for it. However with gas prices as high as they are and it being so early in the season I will elect to sit this one out unless something changes drastically in later runs. As many chasers know Iowa has a 90% fail rate with Tornadoes in the past few years so most will have no problem avoding it.

DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK1130 AM CST SAT FEB 26 2011
VALID 271200Z - 281200Z
...THERE IS A MDT RISK OF SVR TSTMS ACROSS PORTIONS OF EASTERN
OK/MUCH OF AR/SOUTHERN MO/SOUTHERN IL/FAR SOUTHWEST INDIANA/WESTERN
KY/WESTERN TN/NORTHERN MS...
...THERE IS A SLGT RISK OF SVR TSTMS FROM THE SOUTHERN PLAINS TO THE
LOWER/MIDDLE MS VALLEY AND LOWER OH VALLEY...
..SYNOPSIS
CLOSED UPPER LOW CURRENTLY CENTERED OVER CA IS EXPECTED TO
OPEN/SHIFT EASTWARD OVER AZ/NM DURING THE DAY ON SUNDAY...AND TAKE
ON MORE OF A NEUTRAL/SLIGHT NEGATIVE TILT AS IT REACHES THE SOUTHERN
PLAINS/OZARKS LATE SUNDAY NIGHT. A REGIONAL OUTBREAK OF SEVERE
TSTMS...INCLUDING THE POSSIBILITY OF WIDESPREAD DAMAGING
WINDS/STRONG TORNADOES...SEEMS PROBABLE LATE SUNDAY AFTERNOON AND
ESPECIALLY SUNDAY NIGHT.
..SOUTHERN PLAINS/ARKLATEX/OZARKS/MID-SOUTH/LOWER OH VALLEY
THE POSSIBILITY OF WIDESPREAD DAMAGING WINDS AND TORNADOES
/INCLUDING SOME STRONG/...IN ADDITION TO AN INITIAL BOUT OF LARGE
HAIL...WILL BEGIN LATE SUNDAY AFTERNOON...AND CONTINUE WELL THROUGH
THE NIGHT/EARLY MORNING HOURS OF MONDAY ACROSS PORTIONS OF THE
OZARKS/MID-SOUTH TO MIDDLE MS VALLEY/LOWER OH VALLEY.
INITIAL/DIURNAL DEEP CONVECTIVE COVERAGE IS A STILL A BIT UNCERTAIN
ALONG THE DRYLINE ACROSS OK/NORTH TX/FAR SOUTHERN KS DURING THE
DAYLIGHT HOURS...AS MUCH OF THE WARM SECTOR SHOULD REMAIN CAPPED
BENEATH AN ELEVATED MIXED LAYER. NONETHELESS...CURRENT THINKING IS
THAT AT LEAST AN ISOLATED INITIAL THREAT FOR SEVERE TSTMS WILL
DEVELOP BY SUNSET...WITH INITIALLY ISOLATED SUPERCELLS CAPABLE OF
LARGE HAIL AND A TORNADO THREAT ACROSS PORTIONS OF OK/FAR NORTH TX
AND PERHAPS FAR SOUTHERN KS.
OTHERWISE...A SEASONALLY MOIST LOW LEVEL AIRMASS...GENERALLY
CHARACTERIZED BY LOWER 60S F SURFACE DEWPOINTS...WILL BECOME
ESTABLISHED WITHIN A RELATIVELY BROAD WARM SECTOR ACROSS THE REGION
DURING THE AFTERNOON/NIGHT. A CONSIDERABLE INCREASE IN DEEP
CONVECTIVE COVERAGE/INTENSITY IS ANTICIPATED THROUGH THE
EVENING...AS LARGE SCALE FORCING FOR ASCENT/DEEP TROPOSPHERIC WIND
FIELD DRAMATICALLY INCREASE ATTENDANT TO THE ADVANCING UPPER
TROUGH/POLAR JET. WITH DEEP LAYER SHEAR ON THE ORDER OF 50-70
KT...SUFFICIENT INSTABILITY ON THE ORDER OF 750-1250 J/KG MLCAPE
WILL SUPPORT A POTENTIALLY WIDESPREAD SEVERE THREAT. GIVEN STRONG
LOW LEVEL SRH AS AIDED BY A STRENGTHENING 60+ KT LOW LEVEL JET...A
MIXED CONVECTIVE MODE INCLUDING QUASI-LINEAR BOWING
SEGMENTS/LINE-LEADING SEMI-DISCRETE SUPERCELLS WILL BE CAPABLE OF
WIDESPREAD DAMAGING WINDS/STRONG TORNADOES...AS THE SEVERE THREAT
CONTINUES WELL INTO THE EARLY MORNING HOURS OF MONDAY TOWARD THE
MIDDLE/LOWER MS AND TN/LOWER OH RIVER VALLEYS.
..GUYER.. 02/26/2011